Automatic switch



E. A. BOHLMAN AUTOMATI C SWITCH Jan. 12 1926.

Filed Jan. 5, 1922 2. Sheets-Sheet 1 Jan. 12 1926. 1,569,450

- E. A. BOHLMAN AUTOMATIC SWITCH Filed Jan. 5, 1922 2 Sheets-Sheet 2 IN Ip Patented Gleno l2, lQZtl.

ERNEST A. BQIEILMAN, @F GHILGAGQ, ILLTLNQIS, @E Til KEL'LKDGKE- AND SUPPLY CQML'EANY, @F CHICAGU, ILLXNQIS, LL CQRIOLEATIQE @X 11531119563355.

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' To all whom'it may concern:

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, oration.

Be it known that l, Ennnsr A. Bonuaran, a citizen of the United States of America, and a resident of Chicago, county of Coolr, and State of Illinois, have invented certain new and useful Improvements in Automatic Switches, of which the following is a specification. I

My invention relates to selective switches and has to do more particularly with a switch of the step-by-step type that travels in a single direction during the selecting op- The switch of my invention is adapted for use in semi-automatic and calldistributing telephone systems, but I do not wish to be limited to this use, as it may be used for a variety of purposes without de parting from the invention.

Kill

A feature oil in 7 invention is the provision of a particular pawl and ratchet arrangement in association with a motor magnet that advances the wipers step by step over the contacts of a bank.

Another leature or my invention is the provision of a structure comprising a mounting plate which pivotally supports the retaining pawl and also pivotally supports the releasing dog which latter, when actuated by the release magnet, vithdraws the retaining pawl and also the driving pawl to permit the restoration of the wipers to normal. A construction of this kind permits this portion of the switch to be assembled as a unit and secured to the switch without further adjustment.

Another feature of my invention is the provision of an improved spring barrel construction for housing the motor spring of the switch, and a novel adjusting means for the same to place the spring under proper tension.

The above features, as well as others, will he more particularly pointed out in the ensuing specification and appended claims.

For a more complete understanding of my invention, reference may be had to the accompanying drawings, inqwhich like reference characters in the several views denote like parts, and in-which Fig. l is a plan view of a switch provided with the features of my invention;

Fig. 2 is a plan view of the ratchet'and pawl mechanism of the switch showing the apparatus when the release magnet is,par=

the hub 4t, said sector resting Application filed January 3, 129%. Serial 526,532.

with parts brolren away to more clearly illustrate the construction;

1F ig. 6 is a sectional view along the line 6-6 oi? 5.

Referring now more in detail to structure illustrated, the switch coin-prises a mounting plate 2, to which is secured the various operating parts, the said n e also carrying an auxiliary plate 3, to which the hank contacts B is secured by means of suitable screws 4, which bank of contacts B cooperates with the wipers V7 carried by a suitable hub, as will now be described. The wipers W are provided with suitable orifices which permit their losing slipped over the hub 5, but suitably insulated therefrom lay means of the sleeve of insulation 6 and from each other by means of the insulation wash ers 'Z. The hub 5 has integrally formed therewith a cup-shaped portion c, which forms a container for the motor spring 8. A sector 9 is provided having a cen ral oriice of a size to permit its being sli over tween the cup-shaped portion 5 of the said hub 5 and an insulation washer 7, and is secured to the cup portion 5 in proper relation by means or a rivet 10. The wipers Ware clamped place upon the'hub 5 in proper relation by means of the clamping nut ll, which has screw-threaded engagement with threaded portion of the hub 5. The huh t, which carries the sector 9 and wipers W, as a whole is rotatably secured to the mounting 2 by means of a combined motor SPL ngtension and bearing screw 12. The hub 5 is provided with a central opening through which the screw 12 passes, and its one end which is threaded protrudes through a suitable orifice in the mounting plate 2 and is adapted to receive a nut 13, which holds the screw 12in rigid relation with the plate 2 by clamping the said plate between the ltlll shoulder 12' of the screw 12 and the said nut 13. The motor spring 8 fits in the cupshaped portion 5 of the hub 5, the said spring 8 having its one end inserted in a slot 142 of the cup-shaped portion 5 of the hub 5, and its outer end resting in a slot 15 in the head of the bearing screw 12. A cover-cap 16 is provided, which covers the motor spring 8, and a split ring 17 rests in an annular groove 18 in the cup portion 5 and holds the cover-cap 16 in place. The head of the bearing screwv 12 is provided with a pair of slots 15 and 19 at right angles to each other, the slot 19 being of a suitable depth and width for screw-driver use only, for the purpose of adjusting the tension of spring 8 with reference to the moving parts of the switch, the nut 13, of course, being loosened while adjustment is being made and there' after tightened. By providing the shallow slot 19, the deeper one 15 will not be used for adjusting as the slot 15 is of such width to prevent the insertion of a screw driver. If it were so used, the head of post 12 might be spread and cause the switch to bind.

The motor magnet MM, which is adapted to step the wipers W over the contacts of the bank B, includes a heel iron 20, an armature 21, a driving pawl 22 and a suitable electromagnet winding 23, which is secured to the pole piece or heel iron by means of a screw 24-, which has screw-threaded engagement with a suitable tapped orifice in the core. of the electromagnet 23, the said motor magnet MM as a whole being fastened to the mounting plate 2. The armature 21 is pivotally supported upon the pole piece 20 by means of the pivot pin 25. it

.helical spring 26 for holding the armature 21 in its normal position and for placing it under proper tension, has its one end secured to a pin 27 which pin 27 is suitably secured to the heel iron 20 and its other end secured to a screw 28, which screw 28 passes through a suitable orifice in the free end 29 of the armature 21 and has its threaded end extending into and engaging the convolutions of the helical spring 26, the convolutions of .said spring 26 adjusting themselves to the threads'of said screw 28. The screw 28 may be used for adjusting the tension on the armature 21, as is readily apparent. An adjustable stop 30 is provided in the form of a screw, which has screw-threaded engagement with an angular extension 31 integrally formed with the plate 2, said screw 30 being used for properly adjusting the armature 21 in its normal position and its associated driving pawl 22 in proper engagement with the teeth 11 of the sector 9. Thedriving pawl 22 is ad'ustably secured to the angular portion 32 03% the armature 21, and to that end the driving pawl 22 is ,provided with a pair of oblong orifices 33,

through which the clamping screws 34 pass. A clamping member 35 its over the awl 22, and when the proper adjustment or the pawl 22 is secured in relation to the sector 9, which adjustment is permitted through the agency of the orifices 33, the screws 34.

are tightened, securely clamping the pawl 22 in its adjusted position. The pawl 22 is provided with a nose angular in relation to the body portion of the pawl 22, the said nose 40 being normally in engagement with a tooth 411, of which there are a plurality cut in the circumferential face of the sector 9. The driving pawl 22 is constructed oi comparatively thin spring metal, and it is so shaped and its tension is such as to permit its nose at) to engage successive teeth of the sector 9. As the armature 21 of the motor magnet MM vibrates the nose 40 of the pawl 22 en ages successive teeth ll oi the sector 9, stepping the wipers V7 from one contact set of the contact bank B to the next on each back stroke of the armature 21. A stop 42 is secured to the mounting plate 2 against which the sector arm 9 rests when in its normal position, 42 acting as a stop when the wipers l restore to normal and 4-2 also limiting the forward movement of the wipers M7, in that the sector arm 9 engages the said stop 42 when the wipers W are in their farthest advanced position. A pair of interrupter springs a3 and at are insulatingly secured to the heel iron 20 associated with the motor magnet MM, for the usual purposes. A release magnet RM is provided to restore the wipers ll], and comprises a heel iron 45, armature to and an electromagnet at. The armature a6 is pivotally supported upon the heel iron 45 and held in its normal position by means of a helical spring 48, which has one end secured to a pin 4-9 which is secured to the armature l6 and has its other end secured to a screw '50 said screw having its threaded end portion extending into and engaging the end convolutions of the helical spring l8, the said convolutions adjusting themselves to the threads of the screw 50, and by this arrangement the tension of spring 48 may be adjusted as is readily apparent. The screw is supported by a bracket 51, which is secured to the heel iron 4C5.

The retaining pawl 53 and releasing dog at associated with the release magnet RM are assembled as a unit structure upon a supporting plate 55, which latter on being mounted is suitabl and adjustably secured to the mounting plate 2 by means of the screws 56. The releasing dog 54 is in the form of an irregularly shaped plate pivotally secured to the pivot post 57, which is fast on the supporting plate 55. The said releasing dog 54 is held in its normal position against the stop 42 by means of a helical spring 58, which has its one end secured reeaeso to, an arm 59 integrally formed with the releasing dog 54l/and its other end fastened to a pin 60 suitahly secured to the supporting plate 55. The retaining pawl 53 is also pivotally supported upon pivot post 57 and old against displacement upon the post 57 by means of a cotter pin ill. The retaining pawl 53 is spring-pressed into engagement with the circumferential edge of the sector 9 by means of a leaf spring 62, which has its one end secured to an angular extension 63 of the releasing dog 54 by means of the screw 64:, and its free end engaging the retaining pawl 53. When the wipers W are stepped from one contact set to the next, the retaining pawl 53 engages successive teeth 4:1 of the sector 9 to retain the said wipers in engagement with the dinerent sets til-contacts. The retaining pawl 53 is rovided with an extended portion 65, which lies in the path of the armature d6 of the release magnet RM, for purposes as will now he described, To release the switch and permit the wipers V7 to move and rotates the releasing dog 5t about its pivot post 57. An angular extension 67 integrally formed with the releasing dog 54:, due to the movement of the dog 54-, en-

gages the forward end of the driving pawl 22, causing the nose 49 of the driving pawl 22 to disengage the tooth ll of the sector 9, as clearly illustrated in Fig. 2. 'lhe continued movement of the armature d6 of the release magnet RM now causes the extension 66 oil the dog 5d to engage'the ex= tended portion 65 of the retaining pawl 53, also causing the said pawl 53 to rotate ahout its pivot, and when the armature d6 of the release magnet lEtM is in its fully attracted position as illustrated in Fig. 9, the retaining pawl 53 and driving pawl 22 have disengaged the respective teeth oi the sector 9 so thatthe motor spring 8 now restores the wipers M7 haclr to normal o starting position, whereupon the arm 9 or the sector 9 again engages the stop From the ahove description it may he seen that when the nose d0 of the driving pawl has disengaged the tooth of the sector 9 upon the ,artial attraction of the armature lid of the release magnet ltM, that the retaining pawl 53 is still in engagement with a tooth of the sector 9, as clearly illustrated in Fig. 2. Upon the further attraction of release magnet RM, the retaining pawl is fully withdrawn, thus permitting a positive release of the switch wipers W upon the energization of the release magnet ltM,

Referring to Fig. 1, it will he observed that when the switch is at normal, the pawl 22 engages the first tooth of the ratchet sector while the retaining pawl 53 rests on an unserrated portion of sector 9. With the first energization and de-energization of magnet MM, pawl 22 drives the switch a step and pawl 53 then drops into a tooth of sector 9 and holds the sector'while magnet MM energizes and de-energizes to drive another step, the pawl-53 engaging successive teeth in sector 9 as successive steps are made. After the operation of magnet RM and the spring actuated restoration of the switch, an ensuing de-energization of magnet RM will allow spring 58 to restore, releasing plate 54: and the pawls 22 1 and 53 take their normal positions shown in Fig. l.

A set of ofi-normal contacts UN are also provided and assume their alternate posi= tion upon the first step of the wipers \W oilnormal and again assume their normal position when the wipers W restore to normal.

iii/'hile l have illustrated and described my invention in connection with a specific form of switch, I wish it to he understood that I do not wish to he limited to the same, as my invention is applicable in a variety of ways and l, therefore, aim to cover these various applications as come within the spirit and scope of the appended claims.

l laving descrihed my invention what it claim as new and desire to secure hy Letters Patent is:

I... A switch oi? the character described comprising a rotary shalt, a'motor magnet and a driving pawl for advancing said rotary shalt, a release magnet, an adjustahle plate, a releasing dog pivotally secured to said adjustahle plate, a retaining pawl pivotally secured to said plate independently of said releasing dog for holding said shaft an advanced position when moved thereto, means associated with said release magnet for controlling the releasing movement of l engagement with said element for holding said switch in an advanced position, an armature for said release magnet for controlling the releasing movement of said releasing memher, "said retaining pawl and said driving pawl.

3. A switch of the character described i139 comprising a rotary shaft, a motor magnet and a driving pawl for advancing said rotary shaft, a release magnet, a supporting stud, a releasing member pivotally supported upon said stud and spring means for holding said member in its normal position, a retaining pawl pivotally supported upon said stud independently of said releasing member for retaining said shaft in an advanced position, an armature for said release magnet and a part for said member adapted to be engaged by said armature upon the energization of said release magnet to rotate said member about its pivot stud to start the release movement of said member.

4:. A switch of the character described comprising a rotary shaft, a motor magnet and a driving pawl for advancing said rotary shaft, a release magnet, a supporting stud, a releasing member pivotally supported upon said stud and spring means for holding said member in its normal position, a retaining pawl pivotally supported upon said stud independently of said releasing member for retaining said shaft in an advanced position, an armature for said release magnet and a part of said member adapted to be engaged by said armature upon the energization of said release magnet to rotate said member about its pivot stud to start the release movement of said member, and a part of said member adapted to engage said driving pawl to move it out of engagement upon a partial attraction of said armature.

5. A switch of the character described comprising a rotary shaft, a motor magnet and a driving pawl for advancing said rotary shaft, a release magnet, a supporting stud, a releasing member pivotally supported upon said stud and spring means for holding said member in its normal position, a retaining pawl pivotally supported upon said stud for retaining said shaft in an advanced position, an armature for said release magnet and a part of said member adapted to be engaged by said armature upon the energization of said release magnet to rotate said member about the pivot stud to start the release movement of said member, a part of said member adapted to engage said driving pawl to move it out of engagement upon a partial attraction of said armature, and a portion of said retaining pawl adapted to be engaged by the said member upon a further excursion of said armature to cause said'retaining pawl to disengage said switch to permit said rotary shaft to restore to its normal position.

6. A switch of the character described comprising a rotary shaft and a toothed sector associated therewith, a motor magnet including a driving pawl for advancing said rotary shaft, a motor spring for said ees, see

rotary shaft and a spring barrel for enclosing said spring, a pair of slots in one end of said rotary shaft, one of said slots being of shallow depth and of such width to permit the insertion of a screw driver for adjusting purposes, and the other of said slots being of greater depth to permit the insertion of said motor spring for anchoring its one end, and means for anchoring its other end to said spring barrel.

7. A switch of the character described comprising a rotary shaft and a toothed sector associated therewith, a motor magnet including a driving pawl for advancing said rotary shaft, a motor spring for said rotary shaft and a spring barrel for enclosing said spring, a pair of slots in one end of said rotary shaft, one of said slots being of shallow depth and of such width to permit the insertion of a screw driver for adjusting purposes and the other of said slots being of greater depth to permit the insertion of said motor spring for anchoring its one end thereto and being of such width as to prevent the insertion of a screw driver for adjusting purposes, and means for anchoring the other end of said spring to said spring barrel.

8. A traveling switch for automatic telephone exchanges or the like including electrically controlled travel adjusing means, a release magnet, a separately removable release unit supported on said switch indetill pendently of said magnet and having a pivot supporting a release member operable by said armature, holding mechanism for said switch also supported on said pivot independently of said release member and controlled by said release member, means for causing said release member to engage said travel adjusting means, and an armature for said magnet for actuating said release member.

9. A traveling switch for automatic telephone exchanges or the like including electrically controlled travel adjusting means and a releasemagnet, a release unit including a release member and a holding member for said switch, a stud for said release unit for supporting independently and rotatably said members, said stud forming a common axis of rotation for said members, said adj usting means including a travel controlling magnet having armature mechanism adapted to be engaged by said release member, and an armature for said release magnet controlling said last mentioned member.

10. A traveling switch for automatic telephone exchanges orthe like including electrically controlled travel adjusting means, a release magnet, an independently mounted release unit comprising a movable release member and also a holding member for said switch, a travel controlling magnet included in said adjusting means, armature controlled till incense les 11. A traveling switch for automatic telephone exchanges or the hlze including elec trically controlled travel adgustlng release magnet, a supporting men release controlling element supported Hid supporting member independently 01 said magnet, a pair of elements for said switch each holding it in adjusted position and arranged to be engaged in predetermined sequence by said release controlling element, and an armature for said magnet for actuating said release controllin element.

12. A traveling switch for automatic tele phone exchanges or the like including electrically controlled travel adjusting means, a release magnet-mounted on said sv ch, a release controlling unit and means adapted for mounting said release control unit on said switch independently oi? said magnet, a movable release member included in said unit, a movable holding elemei in said unit, controlled by said travel controlling magnet include-d in said adjusting means and having armature mechanism adapted to be engaged by said release member independently of said holding element, and an armature for said release magnet for actuating said release member.

13. The combination With an electrically controlled traveling switch for automatic telephone exchanges or the like, of driving. mechanism for said switch, holding mechanism for said switch, an independent pivotally supported releasing element having means for releasing said driving mechanism and said holding mechanism, a release magnet for actuating said element, mounting means for fastening said magnet to said switch, and means for mounting said element on said switch independently of said release magnet.

14. A traveling sWitc-h for automatic telephone exchanges or the like including electrically controlled travel adjusting means, a release magnet, release element rotatably supported independently of said magnet, a holding element for said switch rotatably supported independently of said release element, a stud forming a common axis or rotation for said elements, a restoring spring for said holding element carried by said release element, a device controlled by said release element for Withdrawing said holding element, and an armature for said magnet for actuating said release element.

Signed by me at Chicago, in the county oi Cook and State of llllinois, this 36th day of December, 1921.

Ell-NEST A. BOHLMAN. 

